The dynamics of pine marten predation on red and grey squirrels

Joshua P. Twining*, W. Ian Montgomery, David G. Tosh

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

2 Citations (Scopus)
115 Downloads (Pure)


Invasive alien species pose one of the greatest threats to global biodiversity. In parts of Europe, introduced eastern grey squirrels (Sciurus carolinensis) have caused regional extinctions of the native red squirrel (Sciurus vulgaris). However, exposure to pine martens (Martes martes) has been demonstrated to reverse the competitive outcome between red and grey squirrels. The mechanism whereby this effect occurs remains unclear. It is hypothesised that direct predation, facilitated by a lack of behavioural response, is the mechanism driving this relationship. We review the literature and reanalyse a new dataset to provide further data on the occurrence of both squirrel species in the scats of pine marten. Both squirrel species occurred in the scats of pine marten confirming its role as a predator of these species. Predation of grey squirrels was significantly higher than red squirrels and was recorded only in spring and summer. Our review provides evidence for the mechanism driving the current decline in grey squirrels in Ireland and Scotland and supports the hypothesis that in the presence of a shared predator, direct predation influences the outcome of species interactions between native red and non-native grey squirrels.

Original languageEnglish
JournalMammalian Biology
Publication statusPublished - 28 Apr 2020


  • Diet
  • Grey squirrel
  • Invasive species
  • Pine marten
  • Predation
  • Prey switching
  • Red squirrel

ASJC Scopus subject areas

  • Ecology, Evolution, Behavior and Systematics
  • Animal Science and Zoology


Dive into the research topics of 'The dynamics of pine marten predation on red and grey squirrels'. Together they form a unique fingerprint.

Cite this